Aerosolizing Nozzle for High Viscosity Fluids
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Solution Overview
Problem
Current technologies face challenges in efficiently generating high concentrations of fine particle respirable aerosols from viscous solutions and solutions with low surface tensions, particularly in delivering surfactant to treat respiratory distress syndrome, as they struggle with viscosity limitations, low output rates, and particle size distribution, failing to provide clinically relevant doses to the adult respiratory tract in a short treatment time.
Innovation Solution
A nozzle design featuring pressurized gas supply channels and a converging annular channel configuration that interacts with the fluid exit orifice to produce a column-like aerosol stream with a gas sheath, preventing droplet formation on the nozzle surface, allowing for efficient aerosolization of high viscosity fluids at high rates, with a mass median aerodynamic diameter (MMAD) of 6 µm or less, and further reducing particle size through solvent evaporation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If mesh-type nebulizers are used to generate aerosols, then soft mists are produced, but the output is limited by viscosity and ceases when viscosity is greater than 2 cSt
Solution Approach 1:
The patent replaces the mesh-type mechanical nebulization system with a jet-type atomizer system that uses compressed gas to generate aerosols. This substitution allows the system to handle high viscosity fluids (greater than 2 cSt) that would clog or stop mesh-type nebulizers, thereby expanding the viscosity range while maintaining aerosol output.
Solution Approach 2:
The patent changes the operating parameters by using adjustable compressed gas pressure (up to 60 psi) and optimized orifice dimensions to enable aerosolization of high viscosity surfactant solutions. This parameter optimization allows the system to deliver clinically relevant doses (100-700 mg) in reduced treatment times while handling viscosities that would fail conventional mesh nebulizers.
2Adaptability or versatility
If jet type atomizers are used to aerosolize viscous solutions, then higher viscosity fluids can be aerosolized, but the output is reduced to about 0.3 ml/minute or less
Solution Approach 1:
The patent optimizes the local geometry of the atomizing orifice and gas interaction zone to enhance aerosol generation efficiency. By carefully designing the orifice dimensions and gas flow patterns at the critical atomization point, the system achieves high aerosol output rates (exceeding 0.3 ml/minute) while maintaining the ability to handle high viscosity fluids, thus resolving the productivity-viscosity tradeoff.
3Productivity
If jet type atomizers recirculate fluid to increase output, then more fluid is processed, but viscosity increases and output decreases
Solution Approach 1:
The patent extracts the aerosolized surfactant from the recirculation loop and delivers it to the patient, preventing the accumulated surfactant from increasing fluid viscosity in the reservoir. This extraction approach allows continuous processing of fluid at high rates without the viscosity buildup that would otherwise reduce aerosol output in closed recirculation systems.
4Quantity of substance
If aerosolized surfactant is delivered to adults, then clinically relevant doses are required, but treatment time becomes excessively long
Solution Approach 1:
The patent prepares the surfactant solution in advance with optimized concentration and viscosity characteristics, and pre-configures the atomizer with optimized orifice dimensions and gas flow settings. This preliminary preparation allows the system to deliver clinically relevant doses (100-700 mg) to adult patients in reduced treatment times without requiring prolonged aerosolization periods.
5Quantity of substance
If capillary aerosol generator heats and evaporates surfactant, then aerosol is produced, but heat-induced degradation occurs and treatment time exceeds one hour
Solution Approach 1:
The patent replaces the thermal evaporation mechanism with a mechanical jet atomization system that uses compressed gas to generate aerosols without heating the surfactant solution. This substitution eliminates heat-induced degradation of the surfactant while maintaining efficient aerosol generation, and reduces treatment time from over one hour to a clinically acceptable duration.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The nozzle achieves 100% aerosol generation efficiency, delivering surfactant at rates of up to 285 mg/min with a narrow particle size distribution, effectively targeting deep lung deposition and reducing treatment time, while maintaining nozzle patency and preventing fluid accumulation.
Implementation Method 1
Aerosol is formed within the aerosolizing space by the liquid stream interacting with pressurized gas exiting from a pressurized gas exit
Implementation Method 2
the evaporation of the liquid from these aerosols to further reduce the particle size and to markedly increase the particle concentration in the suspending gas
Data Source
Figure 1~4
Figure 5~9
Figure 10
AI summary
A nozzle and a method of generating an aerosol from a fluid and a gas by operating the nozzle. The nozzle has an aerosol exit orifice of a larger diameter and a fluid exit orifice of a smaller diameter aligned on a common central axis. A pressurized gas from a pressurized gas exit in close proximity to the fluid exit orifice intersects a fluid jet exiting from the fluid exit orifice at that acute angle and in a distance from the aerosol exit orifice. The method includes aerosolizing a fluid with a viscosity exceeding 4 cSt delivering an inhalable medication at a rate of more than 1 ml/minute, thereby delivering a medication at a mass flow rate of at least 30 mg/minute in form of the fluid particles having a mass median aerodynamic diameter (MMAD) of 6 μιη or less.